低乳糖和无乳糖牛奶、奶制品以及含乳制品中乳糖浓度的高灵敏度酶法测定（K-LOLAC），协作研究：最终行动 2020.08.

Lactose Concentration in Low-Lactose and Lactose-Free Milk, Milk Products, and Products Containing Dairy Ingredients by High Sensitivity Enzymatic Method (K-LOLAC), Collaborative Study: Final Action 2020.08.

机构信息

Megazyme, Bray Business Park, Southern Cross Rd, Bray A98 YV29, Ireland.

出版信息

J AOAC Int. 2022 Oct 26;105(6):1617-1624. doi: 10.1093/jaoacint/qsac070.

DOI:10.1093/jaoacint/qsac070

PMID:35689606

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9605773/

Abstract

BACKGROUND

The AOAC Stakeholder Panel on Strategic Food Analytical Methods issued a call for methods in 2018 for the measurement of lactose in low-lactose and lactose-free products under Standard Method Performance Requirement (SMPR®) 2018.009. Megazyme's Lactose Assay Kit (K-LOLAC) was reviewed and accepted as a First Action Official MethodSM in 2020 (2020.08).

OBJECTIVE

A collaborative study was conducted to evaluate the to evaluate the reproducibility of AOAC Official MethodSM2020.08 for the measurement of lactose concentration in low-lactose and lactose-free milk, milk products, and products containing dairy ingredients.

METHOD

Samples are deproteinated and clarified by treatment with Carrez reagents, and then free glucose is removed using a glucose oxidase and catalase treatment system. Quantification of lactose is based on the hydrolytic activity of β-galactosidase, which hydrolyses lactose to glucose and galactose. Any remaining free D-glucose is first measured using a hexokinase (HK)/glucose 6-phosphate dehydrogenase (G-6PDH)/6-phosphogluconate dehydrogenase (6-PGDH) based assay procedure, and then β-galactosidase is added to hydrolyze the lactose in the same reaction vessel with concurrent measurement of the released D-glucose. The samples analyzed included a number of lactose-free and low-lactose milk samples, lactose-free infant formula, lactose-free milkshake, lactose-free adult nutritional drink, lactose-free cream, and lactose-free cheese.

RESULTS

All materials had repeatability relative standard deviations (RSDr) <7%. The reproducibility relative standard deviation (RSDR) varied from 3.8 to 14.9% with seven of the 10 test samples having an RSDR of <10%.

CONCLUSIONS

The Lactose Assay Kit (K-LOLAC) meets the requirements for reproducibility set out under SMPR 2018.009.

HIGHLIGHTS

The Lactose Assay (K-LOLAC) is a robust, simple, and reproducible method for analysis of lactose in foodstuffs and beverages.

摘要

背景

AOAC 利益相关者战略食品分析方法小组于 2018 年发布了一项方法征集令，要求根据标准方法性能要求（SMPR®）2018.009 测量低乳糖和无乳糖产品中的乳糖。2020 年，Megazyme 的乳糖分析试剂盒（K-LOLAC）被审查并被接受为第一行动官方方法 SM（2020.08）。

目的

进行了一项协作研究，以评估 AOAC 官方方法 SM2020.08 测量低乳糖和无乳糖牛奶、奶制品和含有乳制品成分的产品中乳糖浓度的重现性。

方法

样品用 Carrez 试剂进行脱蛋白和澄清，然后用葡萄糖氧化酶和过氧化氢酶处理系统去除游离葡萄糖。乳糖的定量基于β-半乳糖苷酶的水解活性，该酶将乳糖水解为葡萄糖和半乳糖。首先使用基于己糖激酶（HK）/葡萄糖 6-磷酸脱氢酶（G-6PDH）/6-磷酸葡萄糖酸脱氢酶（6-PGDH）的测定程序测量任何剩余的游离 D-葡萄糖，然后将β-半乳糖苷酶添加到同一个反应容器中，同时测量释放的 D-葡萄糖，以水解乳糖。分析的样品包括一些无乳糖和低乳糖牛奶样品、无乳糖婴儿配方奶粉、无乳糖奶昔、无乳糖成人营养饮料、无乳糖奶油和无乳糖奶酪。